do drug-resistant bacteria prove evolution?

A comment on my post about the “missing link” fossil raises a question that I thought deserved a whole separate response: How can one be involved in medicine, and be a creationist? Don’t mutating viruses and drug-resistant bacteria show that evolution occurs?

Great question. I’m so glad you asked. :) There are two different kinds of evolution, which most people think of lumped together. There is macro-evolution, and then there is micro-evolution. Micro-evolution is the fact that all DNA is always mutating, and that changes do occur within species. Darwin’s famous finches are an example of this: In one setting, one type of beak was most advantageous, and thus most common; under other circumstances, a different kind of beak promoted survival better, and was more common. BUT: This was variation within a species, or kind. The birds were still finches. They didn’t change into chipmunks, or hawks, or even sparrows. And, the original information was still there: they could move back to the first kind of beak when the environment on the island shifted.

This is the kind of evolution that we see in viruses and bacteria. Absolutely, mutations occur in bacterial DNA which make them resistant to antibiotics and give them a survival advantage. Gradually the bacteria without that mutation die out, and the ones with it become more numerous. When penicillin was first discovered, all the gram positive cocci were susceptible to it. Now, 40% of Strep pneumo are resistant. Methicillin-resistant Staph aureus may become the next major public health hazard, as it spreads out of hospitals into the general community. HIV, even since it was first discovered, has mutated to become resistant to the most popular anti-viral medicines.

BUT: Has anyone ever documented a plateful of Strep pneumo mutating into E coli? Or even into Strep pyogenes? I didn’t think so. They mutate, and they exchange information. But they remain separate species, with their own unique characteristics. Staph aureus remains unique in possession of the coagulase enzyme; E coli remains identifiable by its lactose metabolism. They are all separate species and geni; and they definitely are not progressing into amoebae or protozoans.

Macro-evolution, then, is the belief that one kind of life can change into another kind; that by an almost unimaginable series and accumulation of mutations, some random process could turn an amoeba into a plant, and then into a primitive fish, then into an amphibian, and so eventually into “the miraculous race that we are” (to quote G.K. Chesterton’s poem). Macro-evolution is the idea that a species of fish mutated, and turned into a land-walking amphibian. It’s the idea that an ape mutated, and became an intelligent, (occasionally) rational, artistic, human. To me, this sounds like some of the wilder science fiction plots.

So: I believe that God created the world in six 24-hour days, out of nothing. He made every animal kind himself. Part of the natural order that he set up included the ability for DNA to mutate. BUT: When DNA mutates, it generally loses information. The mutation that makes Strep pneumo resistant to penicillins is the loss of a protein (called, in the usual utilitarian manner, penicillin-binding-protein). Dogs are another good example of this. Many of the different breeds we have today resulted from breeding for specific characteristics. Some of these are so extreme that they can’t even breed with each other any more (eg, Great Danes and chihuahuas). But the breeding didn’t add any information; it took it away. The chihuahua lost the ability to grow large; the labradors lost the ability to grow curly hair; and so on. These species and subspecies did not add anything; they lost it.

Thus, it is quite reasonable to believe in the fact of micro-evolution, since it can be seen on a regular basis in the world around us. It can be measured in the lab, and witnessed, and reproduced. This does not in any way necessitate a belief in the theory of macro-evolution, that life originated from non-life, or even that God made the bacteria and then let everything get along from there. Macro-evolution is definitely a theory, since it has not been witnessed or verified by any scientific standard (meaning the standards that applied before scientists got carried away with trying to make a philosophical explanation for the origin of the universe).

(And Tu: I was amused by your saying I don’t sound like a “typical anti-evolutionary theorist.” I got all these ideas here from a very typical creationist teaching organization, Answers in Genesis, and one perhaps innovative creationist biology professor, who liked to shock his students, but is nevertheless very orthodox by our standards.)